This invention relates to a method of preparing an audio disc by writing music in a recordable optical disc.
In the manner, which will later be described in conjunction with FIGS. 1A and 1B, a compact disc (CD) has a diameter of 120 mm and a center hole of 15 mm. In addition, a music program may be recorded in the compact disc at a program area between an inner diameter of 50 mm and an outer diameter of 116 mm. Before and after the program area, namely, inside and outside the area in which the music program is recorded, there are zones which are called a lead in area (LIA) and a lead out area (LOA). A CD player can carry out an automatic musical performance by detecting the zones.
On the other hand, a signal is recorded in the compact disc as a spiral track which is called a physical track. An interval between the adjacent physical tracks is equal to 1.6 xcexcm (about 625 per mm). Accordingly, the compact disc has about 20,000 physical tracks and has a total length of about 5 km.
In general, any book has first a table of contents. If there is no table of contents, it is impossible to easily search where and what is written. In a similar manner in the compact disc, a table of contents is recorded in the compact disc at the most inner circumference thereof. This is called TOC for short. Since the CD player reads contents of the TOC from the compact disc, it is possible to quickly search the compact disc for a target position in response to a command for reproducing a particular movement and to shift or move an optical pickup of the CD player to the target position. The contents of the TOC are recorded in the lead in area (LIA).
In the manner known in the art, an electric equipment such as a personal computer is connected to various peripheral units one of which comprises a memory device or a recording medium. In addition, there are various types of memory devices (recording media). In other words, the memory devices (recording media) are classified into removable media and non-removable media. One of the removable media comprises a compact disc-recordable (CD-R) disc. The CD-R disc is an additionally recordable medium which is compatible with a compact disc read only memory (CD-ROM) disc or a compact disc-digital audio (CD-DA) disc. The additionally recordable medium (optical disc) such as the CD-R disc and a compact disc-rewritable (CD-RW) disc is herein called an additionally recordable optical disc. Although to write information (data) in the CD-R disc requires an exclusive apparatus or a CD-R drive and a writing application, to read the information (data) from the CD-R disc may be carried out by using a CD-ROM drive. Although it is impossible to cancel the data one written, it is possible to frequently add data.
Now, in order to write information (data) in the CD-R disc and to read the information (data) from the CD-R disc, a recording/reproducing optical pickup (which is hereunder merely referred to a pickup) requires for irradiating a laser beam on the CD-R disc.
In general, the pickup of the type described comprises a laser optical source for outputting the laser beam and an optical system for guiding the outputted laser beam to a recording medium such as an optical disc. As described above, it is possible for the CD-R disc to carry out not only reading of information but also writing of information. In the pickup for the CD-R disc, it is necessary to change output or power of the laser beam outputted by the laser optical source either on reading of information or on writing of information. This is because writing of information is carried out by forming pits in a recording layer of the optical disc by irradiating of the laser beam. Accordingly, the output of the laser beam on writing of information is larger than that on reading of information and is, for example, ten to twenty times as large as that on reading of information.
Now, there is a case where data (music) is read out of a predetermined music source and the read data (music) is written in an optical disc (an additionally recordable optical disc) such as a CD-R disc. Under the circumstances, a conventional preparing method for an audio disc comprises the steps of writing all pieces of music on a program area of the additionally recordable optical disc and of writing the LOA and the TOC in the manner which will become clear as the description proceeds in conjunction with FIGS. 2 and 3. However, it is impossible for the conventional preparing method for the audio disc to add any piece of music to the additionally recordable optical disc once the TOC is written on the LIA of the additionally recordable optical disc in the manner which will become clear as the description proceeds in conjunction with FIG. 4.
It is therefore an object of the present invention to provide a preparing method for an audio disc that is capable of adding one or more pieces of music to an additionally recordable optical disc on which TOC is previously written.
Other objects of this invention will become clear as the description proceeds.
The present inventors studied how to add one or more pieces of music to the additionally recordable optical disc on which the TOC is previously written. As a studied result, the present inventors came to a conclusion that such a problem occurs in prior art because a xe2x80x9cdecidedxe2x80x9d TOC is written in the LIA after all pieces of music are written in a program area of the additionally recordable optical disc.
Accordingly, the present inventors reached an idea that it may be possible to add one or more pieces of music to the additionally recordable optical disc many times if a xe2x80x9cspecificxe2x80x9d TOC is written in the LIA. In the mean while, the xe2x80x9cspecificxe2x80x9d TOC means that information indicative of contents of music written in the program area is indefinite or undecided but only information for deciding a xe2x80x9cframexe2x80x9d defining the program area is decided.
On describing the gist of this invention, it is possible to be understood that a method is for preparing an audio disc by writing music in an additionally recordable optical disc having a lead in area (LIA) and a program area. According to an aspect of this invention, the above-understood method comprises the steps of writing a specific TOC in the LIA and of writing music to be recorded in the program area.